Environment Agency Standing Advice Development and Flood Risk - England

March 2007

Development advice for Applicants and Agents

welcome | user flowchart | consultation matrix | sequential test results table| applicant and agent advice

householder and other minor extensions | general surface water drainage information

planning policy statement 25 | flood risk assessment note 1 | flood risk assessment note 2 | flood risk assessment note 3

Applicants and their agents should take part in pre-application discussions with both the Local Planning Authority and the Environment Agency. These discussions can assist all parties to mutual benefit by highlighting early on, instances where for example:

the flood risk Sequential and Exception Tests will be required and is likely to be failed (Note -the Sequential and Exception Tests are not required for ‘minor development’¹ )
the development type is inappropriate for the proposed location
the flood risk to the site is insurmountable
modifications to a proposal at an early stage will make a development proposal acceptable, before the expense of detailed design has been committed to.

For pre-application discussions with the Environment Agency call 08708 506 506 and ask to speak to the Planning Liaison team in the area where the development is planned.

Planning applications must be accompanied by a flood risk assessment (FRA). The table below sets out the FRA requirements for development based on the size of site and the location within the floodplain. Please note that whilst a FRA is essential for developments falling within the cells as set out below, the provision of a FRA will not automatically make that development acceptable in flood risk terms. When a FRA is submitted to us for consideration, we will still object in cases where we consider that the FRA does not or cannot adequately address the flood risk issues.

	Within Flood Zone 3	Within Flood Zone 2	Within Flood Zone 1
All domestic extensions + non domestic extensions with a footprint of less than 250m²	Click here for advisory comments	Click here for advisory comments	No Comment
All applications with a site area less than 1ha	Follow the link to FRA guidance note 3	Follow the link to FRA guidance note 3	Click here for advisory comments
All applications with a site area greater than 1ha	Follow the link to FRA guidance note 3	Follow the link to FRA guidance note 3	Follow the link to FRA guidance note 1

Links to further guidance:

www.environment-agency.gov.uk For information on SUDS best practice, flood proofing and flood resilient construction methods, flood warning, Flood Map and contact details for local Environment Agency offices.
www.ciria.org.uk Check ‘publications’ for details of relevant information
www.ciwem.com/directory/ For information on consulting engineers who may be able to carry out FRAs. This is by no means a definitive list nor should inclusion in this list be taken as Environment Agency endorsement or quality assurance of those parties listed.
www.hrwallingford.co.uk For information on an R&D project on flood risk assessment guidance for new development.

Environment Agency Consents that will also be needed:

Works within Main River and flood defence byelaw distance

Development within byelaw distance from the top of the bank of a designated Main River or from the landward toe of a flood defence will require consent from the Environment Agency. Byelaw distances vary across the country. For information on your local byelaw distances please call 08708 506 506 and ask to speak to a member of the Development Control team in the area where the development is planned.

Works to Ordinary watercourses on site

Development which involves a culvert or an obstruction to flow on an Ordinary Watercourse ² will require Environment Agency consent under the Land Drainage Act 1991. In the case of an Ordinary Watercourse in an internal drainage district, the consent of the Internal Drainage Board instead of the Environment Agency is required. This is in accordance with Section 23 of the Land Drainage Act 1991.

Applicants may apply to the Environment Agency for consent ahead of submitting a planning application and enclose the consent documentation with their FRA. The LPA will formally consult the Environment Agency regarding any planning application submitted, which involves a culvert or an obstruction to flow on an Ordinary Watercourse

Culverting –Environment Agency policy

The Environment Agency has a policy on culverting which strongly discourages the creation of new culverts or extensions to existing culverts except where required for essential access purposes. Culverting increases the risk of flooding by restricting the capacity of the channel to cope with increased flows during flood events and presents significant maintenance problems over the longer term with an on-going risk of blockage. The culvert may also need to be repaired or replaced in the future to maintain or increase its capacity. In addition to the flood risks, culverting may damage the ecology of a watercourse, restricting the scope for water-based fauna and flora to survive and inhibiting the movement of fish. Applicants considering culverting are advised to contact us at the earliest possible stage to discuss the feasibility of the proposals and the likelihood of gaining Land Drainage Act consent.

Any diversion should maintain the original watercourse in cross section, long section and in plan.

Whilst our consent is not required for building over an existing culvert on an Ordinary Watercourse, we strongly advise against this. Building over culverts will obstruct any overland flow route, increasing the likelihood of flooding to the development and its neighbours and there could be difficulties in replacing or maintaining culverts in future.